Conventionally, the precise control of fluid to be administered by means of a catheter to the human body presents major difficulties because of the small flow required to be controlled and which must be easily adjustable.
Several systems are known among which is that consisting of a progressive throttling of the tube either by a lateral or diametric compression or by the introduction of a body which effects the partial blockage of the tube. Also known is the method of longitudinal extension of the tube which closes in on an internal solid nucleus thus reducing the cross sectional passage for the fluid within the tube.
Conventional systems provide a defective and erratic progression of the flow graduation in view of the small passage of flow and also create the possibility of liquid particles being caught in these small passages thus changing the flow conditions after the flow has been adjusted to the required rate.
Such defects result in a lack of reliability of the operation of the flow control during its use, both as to regulation and flow conditions. As a consequence, variations occur when used to administer flow control in medical treatment.
Apart from the possibility of throttling, which may be suitable for large diameter tubes that can be adjusted by squeezing their walls together, the use of a very small hydraulic radius flow regulation device is required, leading to the presence of extremely small interstices that give rise to the previously mentioned defects.
The present invention is a device for regulating and controlling the flow in catheters and similar equipment, designed to obviate the defects mentioned above.